Rethinking water resources management from water-energy nexus perspective — a research and comparison of Jing-Jin-Ji Region of China and California of the United States

The relationship between water and energy is extremely close and complex, especially in water use system. However, the energy consumption of water systems has been ignored in water resources management due to the lack of deep understanding of the water-energy nexus. Based on analysis of waterrelated energy in water use, this paper selected Jing-Jin-Ji region of China and California of the United States to conduct a research study and found that the energy consumption of water use systems accounted for about 16% and 20% of the total electricity consumption of Jing-Jin-Ji region and California, respectively, water use has shifted more energy-intensive. This paper systematically quantified the urban water–energy relationship, analyzed the water supply structure and the energy efficiency and energy consumption in different water system sectors, and found that California’s total water use is 3.3 times that of Jing-Jin-Ji region, but the energy consumption of California’s water systems is only 2.3 times that of Jing-Jin-Ji region. This study suggests that water conservation is a cost-effective way to save energy, and it is necessary to quantitatively analyze the water-energy nexus for a more comprehensive and deep understanding of water resources management.